feat: Add a callback to be called on transaction failure

[dshafik]

This PR adds a new argument to DB::transaction() that allows you to pass in a callback to be executed when the transaction fails:

DB::transaction(function () {
 // do DB stuff
}, onFailureCallback: function () {
    Notification::send($admin, new SomethingImportantBroke());
});

[taylorotwell]

Thanks 👍

[taylorotwell]

I need to revert this one since it's a breaking change on that interface. Sorry!

[negoziator]

Thank you @taylorotwell ! I was just about to comment on it, because of e.g this❤️

[dshafik]

I was going to do that today also, sorry about that! I didn't consider there were outside consumers of the interface, my bad! I'll be more careful in future.

[negoziator]

I was going to do that today also, sorry about that! I didn't consider there were outside consumers of the interface, my bad! I'll be more careful in future.

I think it was very good thinking even though 😀

[rodrigopedra]

@dshafik please consider sending it to master, it is indeed a nice contribution

[negoziator]

@dshafik I was thinking.

Maybe it could be possible to implement a new function e.g transactionWithCallback() 🤔

I didn't think it through quite yet - but i really like the idea of onFailure() callback in the trasaction

[alcaeus]

When looking at the feature in more detail trying to replicate it for the MongoDB integration (which has slightly different transaction handling due to how transactions work in MongoDB), I wasn't quite sure why the callback was preferable to a try-catch block:

try {
    DB::transaction(function () {
        // TODO: World peace
    });
} catch (Throwable $e) {
    // TODO: Save the world
}

I'm sure I'm missing some part of this, maybe @dshafik could help me understand why the above isn't sufficient?

[moe-mizrak]

I created a lightweight package which can be extended (since it is chainable instead of handling it with params):

Basically it wraps DB::transaction() so that we can use it as

$result = TransactionBuilder::make()
    ->attempts(3) // number of attempts
    ->run(function () {
        // your transaction logic
        return 'test';
    })
    ->onFailure(function ($exception) {
        // your onFailure callback logic
        logger()->error($exception->getMessage());
    })
    ->result();

https://github.com/moe-mizrak/transaction-builder